Oxidations with potassium permanganate — metal sulphates and nitrates. β-Selective epoxidation of Δ5-unsaturated steroids
作者:J.A.R. Salvador、M.L. Sáe Melo、A.S. Campos Neves
DOI:10.1016/0040-4039(95)02243-0
日期:1996.1
The β-epoxidation of 3β-acetoxy-Δ5-unsaturated steroids has been achieved with mmerous potassium permanganate-metal sulphates and nitrates with a high degree of stereoselectivity. 5β,6β-Epoxides are formed in a one step reaction in good yields and using very low cost reagents. The best results were achieved with KMnO4/Fe2(SO4)3.nH2O.
Highly efficient epoxidation of unsaturated steroids using magnesium bis(monoperoxyphthalate) hexahydrate
作者:João F.S. Carvalho、M. Manuel Cruz Silva、M. Luisa Sá e Melo
DOI:10.1016/j.tet.2009.01.100
日期:2009.4
Fast generation of epoxides from the corresponding homoallylic and allylic steroidal olefins was developed by using magnesium bis(monoperoxyphthalate) hexahydrate (MMPP) as oxidant suspended in acetonitrile (CH3CN) at reflux temperature. The protocol involves the use of a safe readily available oxidant along with an easy work-up, which renders the process very efficient. Selective 4,5- and 5,6-epoxidations
A Convenient Synthesis of 5,6β-Epoxides of Some Cholesteryl Esters and Δ<sup>5</sup>-Ketosteroid Derivatives by Catalytic β-Stereoselective Epoxidation
作者:Jean-Claude Marchon、René Ramasseul
DOI:10.1055/s-1989-27261
日期:——
The epoxidation of a series of cholesteryl esters by air in the presence of a catalytic amount of a ruthenium tetramesitylporphyrin complex is described. The preparative procedure, which requires only 4 to 5 mol % of the catalyst, leads to high conversion (76 to 94 %) and very high β-stereoselectivity (> 99 %). Similar results are obtained in the epoxidation of 3β-acetoxyandrost-5-ene-17-one, 3β-acetoxypregn-5-ene-20-one, and 3,3-ethylenedioxycholest-5-ene.
Fast, efficient, and highly stereoselectiveepoxidation with H2O2 is reached by manganese coordination complexes with e-rich aminopyridine tetradentate ligands. It is shown that the electronic properties of these catalysts vary systematically with the stereoselectivity of the O-atom transfer event and exert fine control over the activation of hydrogenperoxide, reducing the amount of carboxylic acid
锰配位配合物与富含e的氨基吡啶四齿配体可实现H 2 O 2的快速,高效和高度立体选择性环氧化。结果表明,这些催化剂的电子性能随O原子转移事件的立体选择性而系统地变化,并且对过氧化氢的活化进行了精细控制,从而减少了有效操作所需的羧酸助催化剂的量。
Synthesis of Pregnane Derivatives, Their Cytotoxicity on LNCap and PC-3 Cells, and Screening on 5α-Reductase Inhibitory Activity
作者:Sujeong Kim、Eunsook Ma
DOI:10.3390/molecules14114655
日期:——
available pregnenolone. Compounds 1, 3, 7, 8 and 11-13 were evaluated for cytotoxicity activity towards LNCaP (androgen-dependent) and PC-3 (androgen-independent) prostate cancer cells. Compound 13 showed the highest activity on both LNCaP (IC50 15.17 μM) and PC-3 (IC50 11.83 μM) cell lines. Compound 11 showed weak activity on LNCaP cells (IC 50 71.85 μM) and 8 showed the weak activity on PC-3 cells (IC50